Must-see TV? Variety.com (subscription required) reports that NBC will air The Adventures of Seinfeld & Superman, based on the Internet-exclusive American Express ad shorts, from 8:44-9 p.m. on May 20. The special will mix original footage of Jerry Seinfeld and the cartoon Superman with clips from the Internet shorts. There's no word yet on whether American Express is paying for the ad time, or if NBC is simply viewing it as a way to get Seinfeld back on NBC.